Data and Video-on-Demand (VoD) traffic delivered over mobile networks are projected to grow tremendously in the coming years. Current wireless infrastructures are not provisioned to handle such growth. The projected growth is hence expected to significantly increase the stress on not just the wireless channel, but also the wired backhaul and core of a cellular network. Wireless network operators therefore seek optimizations that can ease this pressure and help defer infrastructure upgrades.
Caches deployed at the edge elements, such as base stations and central controllers (CC) (for example, RNC in a 3G network), of a broadband wireless network are one way of alleviating the traffic stress expected in the wireless backhaul and core due to the projected growth in mobile video traffic. Limits on the sizes of the base station caches and restrictions on frequent upgrades to the hardware necessitate exploring techniques that can increase the hit rates with the growing traffic given the constraints. One way of increasing the hit rates is by increasing the effective cache size by enabling cooperation and sharing of objects among the caching nodes.
Cooperative caching has been studied for traditional wired networks. However, existing approaches assume that the caching nodes are placed on a high-speed network, and hence, that bandwidth available for inter-cache communication is not a constraint. Also, most existing approaches focus on minimizing the average object access latency. In contrast, the bandwidth available for interbase station (inter-BS) or inter-CC communication in the wireless edge is limited, and a need exists to reduce the network traffic in the backhaul and core by reducing the byte miss ratio in the edge.